This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 11-165099, filed Jun. 11, 1999, the entire contents of which are incorporated herein by reference.
The present invention relates to a substrate processing apparatus.
In lithography in manufacturing semiconductor devices, for example, a resist solution is applied to the front face of a substrate such as a semiconductor wafer (hereinafter referred to as xe2x80x9cwaferxe2x80x9d) or the like to form a resist film, a pattern is exposed, and thereafter a developing solution is supplied to the substrate to perform developing processing for the substrate. To perform such a series of processes, hitherto a substrate processing apparatus has been used.
The substrate processing apparatus includes a resist coating processing unit for coating a wafer with a resist solution and processing it, a heat processing unit for subjecting the wafer which has undergone the resist coating processing or exposure processing to heat processing, a cooling processing unit for subjecting the wafer which has undergone the heat processing to cooling processing to a predetermined temperature, a developing processing unit for supplying a developing solution to the wafer to perform developing processing, and the like individually. The wafer is transferred between these processing units and carried in and out by a transfer machine.
Incidentally, there is a possibility that failure in processing due to excessive heat processing for the wafer, that is, so-called over-bake arises if the wafer which has undergone heat processing is not cooled immediately. Hence, conventionally, in order to promptly remove heat stored in the wafer which has undergone heat processing, each tact time of the heat processing unit and the transfer unit is regulated so that the transfer machine is waiting in the heat processing unit before heat processing for the wafer is completed, and thus the transfer machine can immediately transfer the wafer which has just undergone heat processing to the cooling processing unit.
When the carrying out of the wafer which has already undergone cooling processing from the cooling processing unit is delayed for some reason, another wafer which has undergone heat processing can not be immediately carried into this cooling processing unit. As a result, the wafer which has undergone the heat processing merely waits as it is without being carried into the cooling processing unit, thereby causing a possibility that failure in processing due to over-bake occurs.
An object of the present invention is to provide a substrate processing apparatus capable of preventing failure in processing due to over-bake of a substrate which has already undergone heat processing.
To attain this object, the present invention provides a substrate processing apparatus comprising a solution processing unit configured to supply a processing solution to a substrate for processing the substrate, a cooling processing unit configured to subject the substrate to cooling processing to a predetermined temperature, a heat processing unit configured to subject the substrate to heat processing, and a pre-cooling unit configured to cool the substrate before the substrate is subjected to the cooling processing to the predetermined temperature.
According to the present invention, before being carried into the cooling processing unit, the substrate which has just carried out of the heat processing unit is carried into the pre-cooling unit to be cooled. Accordingly, even when the next substrate which has just undergone heat processing can not be carried into the cooling processing unit since cooling processing for the former substrate is not yet completed in the cooling processing unit, the next substrate can be carried into the pre-cooling unit and cooled to such a degree that over-bake does not arise. As for pre-cooling of the substrate, the substrate may be cooled by proper cooling means such as temperature regulated water, Peltier elements, and the like, and in addition to this, for example, the substrate may be cooled by natural cooling.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.